<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="../js/react.development.js"></script>
    <script src="../js/react-dom.development.js"></script>
    <script src="../js/babel.min.js"></script>
  </head>
  <body>
    <div id="test"></div>

    <script type="text/babel">
      class Demo extends React.Component {
        getValue = (e) => {
          e.preventDefault();
          console.log(this.username.value, this.password.value);
        };

        render() {
          return (
            <form onSubmit={this.getValue}>
              <div>
                <label htmlFor="username">用户名：</label>
                <input
                  type="text"
                  id="username"
                  ref={(el) => (this.username = el)}
                />
              </div>
              <div>
                <label htmlFor="password">密码：</label>
                <input
                  type="password"
                  id="password"
                  ref={(el) => (this.password = el)}
                />
              </div>
              <button>提交</button>
            </form>
          );
        }
      }

      ReactDOM.render(<Demo />, document.getElementById("test"));
    </script>
  </body>
</html>
